The present invention relates to a rounded edge “cutting edge” blade that attaches either directly to the bottom of a plow blade mold board or which attaches to the front side of a traditional cutting edge blade that is already mounted to the mold board using the existing mounting bolts and holes. The rounded edge of the blade, when making contact with the ground surface, does not get caught on cracks or irregular surfaces.
Snow plows consist of the main body of a plow, known as a mold board, and replaceable cutting edges that make contact to the ground surface. Cutting edges protect the plow from being dented or bent as it scrapes along irregular ground surface. Once a mold board is bent, it becomes very expensive to repair if repairable at all. Currently cutting edges come in various widths, heights and thicknesses to fit the plow blades on the market ranging from 4 to 12 ft wide, 4 to 10 inches tall, and 0.50 to 3 inches thick, which determines the material they are made from. Cutting edges on the market today are made of polymers, carbon steel, carbide, rubber, polyurethane, or a combination of materials. The rubber or poly composite material edges are molded and have a petroleum base, which makes them more expensive than traditional steel edges. Steel cutting edges can be made of different material, such as carbon steel or carbide, and they come in different gauges and thicknesses as well.
The industry has focused their attention on how to attach the plow to the vehicle, the size of the plow blades, the angle of the plow blade, the hydraulics and mechanics of the mounting system, the control system, and the material the plow blades and cutting edges are made of. Essentially all cutting edges currently in use are made with either a rectangular shape or sharp angle. A rounded edge, when properly constructed and attached to the mold board is superior to the traditional shaped edges because it will bounce over imperfections, and cracks in the surface of roads and will glide over stone, gravel, paver bricks and turf without harming or dislodging the surface. The speed at which the plow is moving, combined with the angle of the blade and weight of the vehicle and plow blade, will generate enough force to remove the material being plowed from the surface with a mold board having a rounded cutting edge. The rounded cutting edge will generate less friction than traditional edges and thus will cause less vibration to the plow blade and vehicle, thus prolonging the life of the equipment. The traditional edges can rip up lane markers, concrete, blacktop, grass, gravel, water main covers, etc. whereas the rounded edge will glide or bounce over them. Potholes and other damage to highways, driveways and paths will be significantly reduced, generating significant savings to municipalities, taxpayers and residences.
The rounded cutting edge of this invention has a cylindrical shape not unlike those set forth in some of the following patent documents, but the particular design of the cylindrical shape, the method of attachment, and the variability of materials are a significant advance in snow plow technology.
U.S. Pat. No. 6,240,662—Borowiak shows mounting brackets welded to a cylinder and attached by bolts passing through holes which must be drilled through the hardened steel of the back of the mold board. It is difficult to drill holes in hardened steel. If a mold board does not have a box design as show in FIG. 2 of Borowiak, the cylinder can not be attached as shown by Borowiak.
U.S. Patent Application Publication No. 2005/0178029—Wightman sets forth a cylinder being attached to the bottom of a traditional cutting edge by pins passing through holes drilled in the cutting edge, which is formed of hardened steel.
The walls of the rounded tube in both the Borowiak patent and the Wrightman published application must be made of steel since round tubes of any polymer, or rubber based composite material would quickly wear or collapse under the weight of the plow. Furthermore, in real life usage, a safety hazard exists in both designs, because once the bottom edge of the cylinder wears through, the front edge of the cylinder will completely dislodge and fall off. When this happens, the strip will ricochet like flying shrapnel that could hit pedestrians, damage vehicles and cause accidents. Further, the arrangements of both Borowiak and Wrightman will lose any advantage a rounded edge affords as soon as the bottom edge wears through, instantly turning the bottom edge of the blade into a vibrating sharp edge with flapping material.
U.S. Pat. No. 8,607,481—Lukasko shows a cylindrical plow blade attachment formed of steel with welded mounting brackets that are attached to the traditional cutting edge using cylindrical fasteners. Holes must be cut into the traditional cutting edge, which can be extremely difficult when the edge is made of hardened steel.
U.S. Pat. No. 8,191,287—Winter et al shows an arrangement for mounting an elastomeric blade edge to a plow mold board.
JP2006233721 (A) shows the use of a rounded edge attached to the bottom of a traditional cutting edge to plow snow. It does not describe an attachment arrangement or the materials to be used.
WO 2013112102 A1—Stalnacke, like the above-mentioned U.S. Pat. No. 8,191,287 sets forth the mounting of an elastomeric blade edge to a plow mold board.
The rounded cutting edge of this invention which is provided by a cylindrically shape member, its method of attachment, and its use of variable materials, which are significant recent advances in snow plow technology, are not disclosed or suggested by the above-mentioned patent documents. The rounded cutting edge of this invention is attached to the mold board by making use of the reinforced holes which are provided in the mold board for attaching cutting edges. It does not require the drilling of holes, or the use of welding. The rounded cutting edge of this invention is attached to the face of an existing cutting edge, or directly to the mold board, while the previous mentioned arrangements require attachment to an existing cutting edge. When the rounded cutting edge of this invention is placed in front of an existing cutting edge, both edges engage the surface being plowed, such that they will wear at the same pace, without the result of any steel being separated from the plow. The rounded cutting edge of this invention will retain its shape and effectiveness throughout the plows usage, which is usually 2 inches of wear like the traditional cutting edges wear.